Implement DeferredPool, which will be used to wait on certain deferreds to prevent shutdown
Add a deferredpool to supervisor
Delay shutdown until supervisor jobs are done
Add a comment explaining why the supervisor service works
Document coiterate ivar in supervisor
Turn Supervisor into SupervisorService, but add a ISupervisor interface since the controller doesn't depend on the service, just the Supervisor part
Fix other tests
Merge branch 'master' into auto-559-defer-sigterm-on-server-launches
Do not check that self.deferred_pool is not None, since it will not be None
lint fixes
Fix docstring reference
Merge pull request #353 from rackerlabs/auto-559-defer-sigterm-on-server-launches

Auto 559 defer sigterm on server launches